<!DOCTYPE html>
<html lang="zh-cn">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>外部css</title>
    <link rel="stylesheet" href="./css/demo23.css">
</head>

<body>
    <p>李昊哲</p>
    <p>刘晓兰</p>
</body>

</html>